Blood tests capable of identifying biological changes linked to Alzheimer’s disease are now available in Brazil, but only through private laboratories. The tests, which range in price from R$1,800 to R$5,000 (approximately USD 320 to USD 890 at recent exchange rates), detect biomarkers such as beta‑amyloid and phosphorylated tau proteins in blood samples.
How the tests work
The assays measure biomarkers like p‑tau217, a form of the tau protein that correlates strongly with amyloid plaque buildup in the brain. A blood sample is collected in Brazil and, in some cases, sent abroad for analysis; for example, Fleury’s Precivity AD2 test processes samples in the United States. Other labs, such as Richet (Rede D’Or) and Dasa, offer p‑tau217‑focused tests priced at R$1,800 and ranging from R$841 to R$4,500 respectively.
Indications and limitations
Medical experts say the tests are intended for patients who already show cognitive decline or have undergone clinical evaluation, not for asymptomatic screening. Neurologist Fábio Henrique Porto of the Brazilian Alzheimer Association (Abraz) notes that the exams can help doctors confirm whether cognitive symptoms relate to Alzheimer’s, complementing traditional clinical assessment.
Geriatrician Leonardo Oliva of the Brazilian Geriatrics and Gerontology Society (SBGG) emphasizes that p‑tau217 is currently the most accurate blood biomarker for confirming Alzheimer’s in symptomatic patients. He adds that the blood test can enable earlier diagnosis compared with invasive lumbar puncture or costly amyloid PET scans, which remain unavailable through Brazil’s Unified Health System (SUS) and are not covered by private health plans.
Comparison with existing diagnostic methods
Before blood tests became available, biomarker investigation relied on cerebrospinal fluid analysis via lumbar puncture or amyloid PET imaging. A lumbar puncture typically costs between R$2,000 and R$3,000, while an amyloid PET scan can reach R$10,000 to R$12,000. Both procedures are inaccessible through SUS and lack private‑plan coverage.
Expert perspectives
Oliva points out that combining blood biomarkers with clinical evaluation can raise diagnostic accuracy from about 70‑75% with clinical assessment alone to up to 91%. Porto highlights the potential of blood tests to expand correct diagnosis outside major urban centers, where infrastructure for PET scans or lumbar punctures is limited.
Relation to emerging treatments
The availability of blood tests could broaden access to recently approved Alzheimer’s drugs such as lecanemabe (Leqembi) and donanemabe (Kisunla), which target early‑stage disease by removing beta‑amyloid plaques. These medications are also not provided through SUS nor covered by private insurance.
Regulatory status
Brazil’s health regulator, Anvisa, has registered approximately 30 products for detecting various Alzheimer’s biomarkers, including both blood‑based assays and cerebrospinal fluid tests. However, the regulator does not recommend using blood tests for population‑wide screening in asymptomatic individuals, pending further validation in more representative cohorts.
Single-source reporting: based on Folha de S.Paulo.